SU1750756A1 - Method of producing aluminum alloy hot-rolled strips - Google Patents

Abstract

Usage: hot rolling aluminum alloy strips. SUMMARY OF THE INVENTION: An AMG 2 aluminum alloy ingot is heated, hot rolling is carried out in several passes and winding into a roll. Rolling in the last pass is carried out at 420-430 ° C with a deformation rate of 100-120s 1 and with a relative degree of reduction 50-70%, 1 tab.

Description

The invention relates to the hot working of metals by pressure, mainly to the hot rolling of strips of aluminum alloys.

A known method for producing hot rolled strips of aluminum alloys, including heating ingots, hot rolling, winding into a roll and annealing coils to obtain the required level of plastic properties of the strips. The annealing operation requires additional energy consumption, and also inhibits the performance of all rolling equipment.

The closest in its technological essence to the present invention is a method of producing hot rolled sheets of aluminum alloy AMG2, including heating of ingots, rough and finishing hot rolling, winding into a roll at a temperature above 350 ° C and holding the strip in a roll at this temperature. strip at this temperature, replacing the annealing operation, ensures that the process of recrystallization and

obtaining the required level of plastic properties.

The disadvantage of the known method is that the long exposure of the strip in the coil lengthens the technological process and restrains the growth of productivity of all rolling equipment.

The purpose of the invention is to increase productivity while maintaining a given level of ductility of the strips.

This goal is achieved by the fact that in the method involving heating the ingot, hot rolling over several passes and winding into a roll according to the invention, the last pass was rolled at a temperature of 420-430 ° C, with a deformation rate of 100-120 sec 1 and relative the degree of reduction of 50-70%.

The method is carried out as follows.

The ingots of the AMG2 alloy are heated to the temperature of the start of hot rolling, then rolled on a semi-continuous or reversing mill to the final thickness.

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Rolling in the last pass is carried out at 420-430 ° C, with a strain rate of 100-120 and with a relative degree of reduction of 50-70%, which ensures recrystallization immediately after the termination of hot deformation at the exit from the cage.

The table shows the degree of recrystallization of the AMG2 alloy strips at the exit from the stand, depending on the temperature-rate and deformation parameters of rolling in the last pass according to the known and proposed method.

It follows from the table that the bands rolled according to the claimed method, at the exit from the cage after the last passage, are completely recrystallized (the degree of recrystallization is 100%). An increase in the technological parameters of rolling over the established limits (temperature 420-430 ° C, strain rate 100-120, relative degree of reduction 50-70%) does not increase the softening of the bands (degree of recrystallization 100%), but causes only an increase in energy consumption. Therefore, the use of this area of technological parameters is not economically feasible. Experimental rolling showed that the bands rolled by the proposed method have the required level of plastic properties (conditional yield strength of 90-100 MW / m2, elongation 22-24%), not inferior to the properties of the bands rolled by a known method.

Example. The AMG2 alloy strips of size G, 2x1300 mm were rolled on a 2800 semi-continuous broadband mill. The rolling speed in the last stand of a continuous group of 3.3 m / s, in the last pass, the strip is rolled from 5 to

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3.2 mm. The deformation temperature in the last pass is 365 ° C, the deformation rate is 50, the relative reduction is 36%. The specified temperature-rate and deformation parameters of rolling in the last pass provide a recrystallization rate of 2% at the exit from the stand, which necessitates keeping the strip in a coil at the temperature of the end of rolling in order to obtain a fully recrystallized state. In order to obtain a strip completely recrystallized at the exit from the last stand of the continuous group, the following rolling mode is prescribed. The strip in the last pass is rolled from 6.4 to 3.2 mm, the rolling speed is prescribed 6.5 m / s. The deformation temperature in the last pass is 425 ° C, the deformation rate is 101 s, the relative reduction is 50%. The degree of recrystallization of the strip at the exit of the cage after the last pass, rolled according to the proposed mode, is 100%. The need for a long strip shutter speed in a roll disappears, the exclusion of which makes it possible to increase the productivity of all rolling equipment.

Claims (1)

Claims The method of obtaining hot rolled strips of aluminum alloy AMG 2, which includes heating the ingot, hot rolling in several passes and winding into a roll, characterized in that, in order to increase productivity while maintaining a given level of plasticity, rolling in the last pass is carried out 420-430 ° C with a strain rate of 100-120 and with a relative degree of reduction of 0 50-70%. five 0 five Table continuation